1. Field of the Invention
This invention relates to a process for producing a composite film which has a textile surface and which can be used for example for producing diaper pants or as closure tapes.
2. The Prior Art
U.S. Pat. No. 5,683,787 describes a process wherein a continuous fibrous web is applied to an elastic film web. The elastic film web is composed of a thermoplastic elastomer, and the fibrous web is adhered or welded thereto at spaced apart contact sites. The laminate is subsequently extended up to close to the breaking extension limit of the fibers of the fibrous web and untensioned or relaxed again. The stretching, which is also referred to as activation, serves to improve the extensibility of the composite film.
U.S. Pat. No. 5,344,691 describes a process for producing a composite film which has elastic and nonelastic regions at predetermined sites. The first step is to produce, preferably by coextrusion, a laminate which has an elastic layer of a thermoplastic elastomer and at least one cover layer of a thermoplastic polymer of low elasticity, for example a polyolefin. Predetermined regions are subsequently activated by stretching to create a composite film having extensible and less extensible sections.
Existing processes expose not only the fibrous web but also the elastic layer to great stress in the course of the mechanical activation. It is consequently necessary to use elastic films which are sufficiently thick to withstand the mechanical stresses. When apertured and hence air-pervious films are used, there is a danger of cracking between the apertures.